Brass, copper-tin, and copper plating bath brightener



United States Patent i 2,980,448 BRASS, COPPER-TIN, AND COPPER PLATINGBATH BRIGHTENER Daniel R. France, 1650 W. 3rd St., Brooklyn 1, N.Y. NoDrawing. Filed Apr. 8, 1959, Ser. No. 804,880 8 Claims. (Cl. 204-44)This invention relates to new and useful improvements in plating bathsand plating bath brighteners for brass, copper-tin and copper plating.

An object of the invention is to provide a single basic brightener whichwill operate satisfactorily and with equal results in brass, copper-tinand copper plating baths.

Another object of the invention is to accomplish what has long beendesired in the art of electroplatingto deposit copper, copper-tin.andbrass in such a manner as to cause a smoothing out of the surfaceimperfections of the underlying metal plated and to maintain thissurface over wide ranges in current densities and temperatures.

Still another object is to provide a brightener which will depositcopper, copper-tin or brass in a fully bright condition from the platingbath without agitation or periodic reverse of the bath.

Other objects, advantages and features of the invention will be apparentfrom the specification and appended claims.

The general composition of the brightener is the metals lead, arsenic,tin and vanadium and organic materials alkyl-aryl amine type wettingagent and ethylenediaminetetra acetic acid (Versene). However, eithertellurium, selenium, antimony or bismuth in the same quantities as thevanadium in the examples hereinafter set forth can be used to replacethe vanadium and good results still be obtained.

More specifically, the composition of the brightener is as follows:

Ounces Sodium hydroxide 16 Arsenic trioxide 6 Lead subacetate .6 Sodiumstannate 3 Vanadium pentoxide .2 Ethylenediaminetetra acetic acid(Versene) 1.6 Wetting agent (alkyl-aryl amine type) 3.2

Water to make one gallon.

The plating bath formulas, the proportions in which they should bemaintained and the amount of brightener needed to produce the bestresult is as follows:

Copper plating bath Ounces per gallon Free NaCN 4.8 CuCN 8.0 NaOH 8.0Arsenic (as metal) .015 Lead (as metal) .0034 Vanadium (as metal) .0009Tin (as metal) .02

Wetting agent Patented June 20, 1961 Ounces per gallon Tin (as metal).006 Vanadium (as metal) .0003 Wetting agent i .16 Ethylenediaminetetraacetic acid (Versene) .08

Yellow brass bath Free NaCN 4.8 CuCN 8.0 NaOH 10.0

ZnCN g .5 KNaC H O 4H O 2.0 Arsenic (as metal) .015 Lead (as metal).0034 Tin (as metal) L .02 Vanadium (as metal) .0009 Wetting agent .5Versene .25

All three types of plating baths are worked at temperatures from 135 to160 degrees Fahrenheit and all three produce bright plated deposits atfrom 3 to a.p.s.f. Agitation or periodic reverse is not required. Thefree NaCN is kept at the same ratio to copper cyanide in all threeplating baths. (.6 ounce of free sodium cyanide for each one ounce ofcopper cyanide which is contained in the plating bath). This ratio iskept regardless of any other metal present in the bath such as ZnCN inthe brass or NaSnO in the bronze.

The brightener provides bright deposits at the temperatures of the bathsto degrees). High C/D can be employed without burningthe deposit.Excellent color control is provided overwide range in C/D. in the brassand bronze baths. There is 100% anode efliciency due to high toleranceto a high free NaCN content. A leveling of the basic metal occurs by themetal being deposited and the metal is deposited in a fully brightcondition.

As above mentioned, the vanadium in the brightener can be replaced bytellurium, selenium, antimony or bismuth. Examples of plating bathsshowing such replacement are as follows:

Copper plating bath 7 Ounces per gallon Free NaCN 4.8 CuCN 8.0 NaOH 8.0Arsenic (as metal) .015 Lead (as metal) .0034 Tellurium (as metal) .0009Tin (as metal) .02 Wetting agent .5 Ethylenediaminetetra acetic acid .25

Copper-tin bath (bronze) Free NaCN V 1.8 NaSnO 3.5 CuCN 3.0 KNaC4H4O54HO 6 .0 NaOH 7 1.5 Arsenic (as metal) .005 Lead (as metal) .001 Tellurium(as metal) .003 Tin (as metal) .006 Wetting agent .16Ethylenediaminetetra acetic acid 3 Yellow brass bath Ounces per gallonFree NaCN 4.8 CuCN 8.0

NaOH 10.0

ZnCN .5 KNaC H O 4H O 2.0 Arsenic (as metal) .015 Lead (as metal) .0034Tin (as metal) .02 Tellurium (as metal) .0009 Wetting agent .5Ethylenediaminetetra acetic acid .25

Copper plating bath Free NaCN 4.8

CuCN 80 NaOH 8.0 Arsenic (as metal) .015 Lead (as metal) .0034 Selenium(as metal) .0009 Tin (as metal) .02 Wetting agent .5Ethylenediaminetetra acetic acid .25

Copper-tin bath (bronze) Free NaCN 1.8 NaSnO 3.5 CuCN 3.0 KNaC H O 4H O6.0 NaOH 1.5 Arsenic (as metal) .005 Lead (as metal) .001 Selenium (asmetal) .003 Tin (as metal) .006 Wetting agent .16 Ethylenediaminetetraacetic acid .08

Yellow brass bath Free NaCN 4.8 CuCN 8.0 NaOH 10.0 ZnCN .5 KNaC H O 4H O2.0 Arsenic (as metal) .015 Lead (as metal) .0034 Tin (as metal) .02Selenium (as metal) .0009 Wet-ting agent .5 Ethylenediaminetetra aceticacid .25

Copper plating bath Free NaCN 4.8 CuCN 8.0 NaOH 8.0 Arsenic (as metal).015 Lead (as metal) .0034 .Antimony (as metal) .0009 Tin (as metal) .02Wetting agent .5 Ethylenediaminetetra acetic acid .25

Copper-tin bath (bronze) Free NaCN 1.8 NaSnO 3.5 CuCN 3.0 KNaC I-I O 4HO 6.0 NaOH 1.5 Arsenic (as metal) .005 Lead (as metal) .001 Antimony(asmetal) .003 Tin (as metal) .006 Wetting agent .16Ethylenediaminetetraacetic acid .08

4 Yellow brass both Ounces per gallon Free N aCN 4.8 CuCN 8.0 NaOH 10.0

ZnCN .5

KNaC H O 4H O Arsenic (as metal) .015 Lead (as metal) .0034 Tin (asmetal) .02 Antimony (as metal) .009 Wetting agent .5Ethylenediaminetetra acetic acid .25

Copper plating bath Free NaCN 4.8 CuCN 8.0 NaOH 8.0 Arsenic (as metal).015 Lead (as metal) .0034 Bismuth (as metal) .0009 Tin (as metal) .02Wetting agent .5 Ethylenediaminetetra acetic acid .25

Copper-tin bath (bronze) Free N aCN 1.8 NaSnO 3.5 CuCN 3.0 KNaC H O 4I-IO 6.0 NaOH 1.5 Arsenic (as metal) .005 Lead (as metal) .001 Bismuth (asmetal) .0003 Wetting agent .16 Ethylenediaminetetra acetic acid .08

Yellow brass bath Free NaCN 4.8

CuCN 8.0

NaOH 10.0

ZnCN .5

KNaC H O 4H O 2. 0 Arsenic (as metal) .015 Lead (as metal) .0034 Tin (asmetal) .02 Bismuth (as metal) .0009 Wetting agent .5Ethylenediaminetetra acetic acid .25

Having described my invention, I claim: 1. A brightener for plating ametal selected from the group consisting of copper, copper-tin and brasscomprising the following in the following proportions, sixteen ouncessodium hydroxide, six ounces arsenic trioxide, six tenths ounce leadsubacetate, three ounces sodium stannate, two tenths ounce vanadiumpentoxide, one and six tenths ounces ethylenediaminetetra acetic acidtetrasodium salt, three and two tenths ounce alkyl-aryl amine typewetting agent and water sufficient to make one gallon of brightener.

2. A copper plating bath comprising the following in the followingproportions per gallon: 4.8 ounces free sodium cyanide, 8.0 ouncescopper cyanide, 8.0 ounces sodium hydroxide, .015 ounce arsenic (asmetal), .0034 ounce lead (as metal), .0009 ounce vanadium (as metal),.02 ounce tin (as metal), .5 ounce wetting agent and .25 ounceethylenediaminetetra acetic acid tetrasodium salt.

3. A copper-tin plating bath comprising the following in the followingproportions per gallon: 1.8 ounces free sodium cyanide, 3.5 ounces NaSnO3.0 ounces copper cyanide, 6.0 ounces Rochelle salts, 1.5 ounces sodiumhydroxide, .005 ounce arsenic (as metal), .001 ounce lead (as metal),.003 ounce vanadium (as metal), .006

5 ounce tin (as metal), .16 ounce wetting agent and .08

ounce ethylenediaminetetra acetic tetrasodium salt.

4. A yellow brass plating bath comprising the following in the followingproportion per gallon: 4.8 ounces free sodium cyanide, 8.0 ounces coppercyanide, 10.0 ounces sodium hydroxide, .5 ounce zinc cyanide, 2.0 ouncesRochelle salts, .015 ounce arsenic (as metal), .0034 ounce lead (asmetal), .02 ounce tin (as metal), .0009 ounce vanadium (as metal), .5ounce wetting agent and .25 ounce ethylenediaminetetra acetictetrasodium salt.

5. A yellow brass plating bath comprising the following in the followingproportions per gallon: 4.8 ounces free"sodium cyanide, 8.0 ouncescopper cyanide, 10.0 ounces sodium hydroxide, .5 ounce zinc cyanide, 2.0ounces Rochelle salts, .015 ounce arsenic (as metal), .15 ounce wettingagent, .25 ounce ethylenediaminetetra acetic tetrasodium salt and .0009ounce of a metal (as metal) from the group consisting of selenium,bismuth, antimony and tellurium.

6. A copper plating bath comprising the following in the followingproportions per gallon: 4.8 ounces free sodium cyanide, 8.0 ouncessodium hydroxide, .015 ounce arsenic (as metal), .0034 ounce lead (asmetal), .02 ounce tin (as metal), .5 ounce Wetting agent, .25 ounceethylenediaminetetra acetic acid tetrasodium salt and .0009 ounce of ametal (as metal) from the group consisting of selenium, bismuth,antimony and tellurium.

7. A copper-tin plating bath comprising the following in the followingproportions per gallon: 1.8 ounces free sodium cyanide, 3.5 ounces NaSn03.0 ounces copper cyanide, 6.0 ounces Rochelle salts, 1.5 ounces sodiumhydroxide, .005 ounce arsenic (as metal), .001 ounce lead (as metal),.006 ounce tin (as metal), .16 ounce Wetting agent, .08 ounceethylencdiaminetetra acetic tetrasodium salt, and .0003 ounce of a metal(as metal) from the group consisting of selenium, bismuth, antimony andtellurium.

8. A brightener for plating a metal selected from the group consistingof copper, copper-tin and brass comprising the following in thefollowing proportions: .6 ounce lead subacetate, 6.0 ounces arsenictrioxide, 3.0 ounces sodium stannate, .2 ounce vanadium pentoxide, .25ounce ethylenediaminetetra acetic acid tetrasodium salt, .5 ouncewetting agent, 16.0 ounces sodium hydroxide and water to make one gallonof brightener.

References Cited in the file of this patent UNITED STATES PATENTS2,841,542 Manquen July 1, 1958 2,881,122 Foulke et a1 Apr. 7, 1959FOREIGN PATENTS 2,778,788 France Ian. 22, 1957 2.838.448 France une 10,58

1. A BRIGHTENER FOR PLATING A METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, COPPER-TIN AND BRASS COMPRISING THE FOLLOWING IN THE FOLLOWING PROPORTIONS, SIXTEEN OUNCES SODIUM HYDROXIDE, SIX OUNCES ARSENIC TRIOXIDE, SIX TENTHS OUNCE LEAD SUBACETATE, THREE OUNCES SODIUM STANNATE, TWO TENTHS OUNCE VANADIUM PENTOXIDE, ONE AND SIX TENTHS OUNCES ETHYLENEDIAMINETETRA ACETIC ACID TETRASODIUM SALT, THREE AND TWO TENTHS OUNCE ALKYL-ARYL AMINE TYPE WETTING AGENT AND WATER SUFFICIENT TO MAKE ONE GALLON OF BRIGHTENER. 